The Deep Space 1 (DS1) spacecraft was the
first project launched as part of NASA's New
Millennium program. Its mission was to
evaluate 12 new technologies on board the
spacecraft, and to use these technologies to
perform a flyby of the asteroid Braille
(1992 KD). The extended mission called for a
flyby of the comet Borelli. One of the 12
technologies that was proven during its
mission was the ion propulsion system.

NSTAR Ion Engine

DS1 used the NSTAR ion
engine as primary propulsion for its
mission. The ion engine propelled DS1
263,179,600 km (163,532,236 miles) at speeds
up to 4.5 km/s (10,066 mph). The NSTAR
engine, developed by GRC's ion propulsion
program, is 30 cm in diameter and weighs
only 8.3 kg (about 18 lbs). The engine was
powered by two solar arrays, which output
2500 W. The ion engine used 2100 W of this
power. This is the same as thirty-five 60 W
light bulbs. Due to the engine's high
efficiency it needed only 81 kg (178 lbs) of
xenon propellant to achieve its mission. If
there were more xenon on board the engine
could have produced a top speed of 30 km/s
(67100 mph).